<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    
        .con{
            width: 200px;
            height: 200px;
            background-color: gold;
            /*overflow: hidden;*/
           
        }

        .box{
            width: 120px;
            height: 50px;
            background-color: green;
            margin: 75px auto;
        }

        .clearfix:before{
            content: "";
            display: table;
        }
    
    </style>
</head>
<body>
    


    <div class="con clearfix">

        <div class="box"></div>

    </div>

</body>
</html>